docs: def create_section(self, name, overwrite=True):
          """
          create and return a new sub-section of this manifest, with the
          given Name attribute. If a sub-section already exists with
          that name, it will be lost unless overwrite is False in which
          case the existing sub-section will be returned.
          """
  
          if overwrite:
              sect = ManifestSection(name)
              self.sub_sections[name] = sect
  
          else:
              sect = self.sub_sections.get(name, None)
              if sect is None:
                  sect = ManifestSection(name)
                  self.sub_sections[name] = sect
  
          return sect